2018 Indicators: SST's / MSLP / Sal / Steering / Shear / Instability (Graphic updates at first post)

[psyclone]

The standard barrage of premature season cancel posts have a good chance of verifying this year. I'll take it.

I prefer calling the prospect “season slow” rather than “season cancel”.

Naturally you're correct but you're also not one of the usual suspects throwing in the towel in mid to late July. The weather is a game of odds as we know. Low risk is better than moderate or high risk but low risk does not = no risk.

[KAlexPR]

The standard barrage of premature season cancel posts have a good chance of verifying this year. I'll take it.

A broken clock is right twice a day.

[KWT]

Across west Europe this summer has thus far been very similar to 2006, given the ENSO state, at least in our neck of the woods, its a good fit.

[TheStormExpert]

2006, 2009, and 2014 all look like good analogs at the moment. 1985 is becoming seemingly less likely.

[Eric Webb]

The AMM is usually a pretty good indicator of MDR activity and is the 2nd leading mode of variability in the Atlantic behind the AMO, to see it in record low territory is just another sign of a quiet season in terms of overall activity but it says little about the steering pattern. I'd also like to mention however that -AMO/-AMMs are actually more conducive to less recurving TCs out of the MDR because in order to get a -AMO/-AMM you need strong trades which also means you need a bigger AB high which would tend to steer TCs further west. Oth, the El Nino-ish atmosphere that's becomes well entrenched globally signals at least to me that there will be more troughs than normal attempting to emerge off the eastern seaboard to at least temporarily breakdown the AB high.

It's certainly an interesting lesser known observation amongst the met community and blogosphere that while you get significantly less storms in the MDR during -AMM/-AMOs, ones that do form are more likely to impact land. The ENSO steering pattern relationship is more widely recognized but is apparently just as important as the AMO/AMM.

 https://twitter.com/DanVimont/status/1013878561353207809

[SFLcane]

 https://twitter.com/RaleighWx/status/1014118968259416064

[TheStormExpert]

With a warmer than average Subtropical Atlantic will it mean anything? Still could yeild somewhat more ideal conditions in the Tropical Atlantic but what I’ve noticed over the past several moths is you get these small warming blips only to cool back down for a long period.

[KWT]

I'm not buying that sst map, any map that has the water around Ireland/England cooling down as they have had record breaking warm temps is more than a little suspect..

[Kingarabian]

I'm not buying that sst map, any map that has the water around Ireland/England cooling down as they have had record breaking warm temps is more than a little suspect..

Agree. All the weather organizations in the world should get together, sit down, and agree on what SST climo to use. There's so much variance, that it's hard to know what's going on. That shouldn't be the case.

[Ntxw]

That map is not actual sst map, but rather 7 day anomaly change.

[KWT]

That map is not actual sst map, but rather 7 day anomaly change.

Very true, still inaccurate for my neck of the woods though in a big way and obviously you can extralopate that to an extent. Record heat does not normally lead to ssts cooling..
Doesn't exactly give confidence to what it shows on abigger picture.

[Ntxw]

That map is not actual sst map, but rather 7 day anomaly change.

Very true, still inaccurate for my neck of the woods though in a big way and obviously you can extralopate that to an extent. Record heat does not normally lead to ssts cooling..
Doesn't exactly give confidence to what it shows on abigger picture.

Cooling is misleading on that map. If it was record warmth and the past 7 days it cooled to really really warm, net cooling but still much warmer than average.

[StruThiO]

 https://twitter.com/philklotzbach/status/1014910762328788992

[tarheelprogrammer]

African waves only seem to be getting stronger, not weaker. In inactive years, is it the opposite? Is there any documented cases of waves being this strong, but the season staying quiet? Just curious.

[Hammy]

African waves only seem to be getting stronger, not weaker. In inactive years, is it the opposite? Is there any documented cases of waves being this strong, but the season staying quiet? Just curious.

1997 is the only year that I can think of, where we had a lot of strong tropical waves coming off (including several almost-depressions) yet had a quiet season--but that year was being blasted with wind shear thanks to a record (at the time) Nino.

[Siker]

Saw an interesting post over on Weather Underground yesterday that linked to this CPC page monitoring the "African InterTropical Front". Apparently the eastern portion of this has been at a record northern latitude recently. Here's the link and the most recent summary below:

http://www.cpc.ncep.noaa.gov/products/i ... itcz.shtml



"From June 21-30, the ITF exhibited a large northward advancement in western Africa, and a significant advancement in eastern Africa during the end of June. The mean western (10W-10E) portion of the ITF was approximated at 18.2N, rising well above the climatological normal position by 1.6 degrees. The mean eastern (20E - 35E) portion of the ITF was approximated at 16.6N, very much above the climatological mean position (14.4N) by a remarkable 2.2 degrees. This latest eastern ITF portion anomaly is another significant jump northward from what was already a record postion for mid-June going back to the start of the ITF record in 1989. Figure 1 shows the current position of the ITF relative to the mean climatological (black) position during the 3rd dekad of June and its previous (yellow) position during the 2nd dekad of June. Figures 2 and 3 are time series, illustrating the mean latitudinal values of the western and eastern portion of the ITF, respectively, and their seasonal evolution compared to climatology since April, 2018."

[NotSparta]

Saw an interesting post over on Weather Underground yesterday that linked to this CPC page monitoring the "African InterTropical Front". Apparently the eastern portion of this has been at a record northern latitude recently. Here's the link and the most recent summary below:

http://www.cpc.ncep.noaa.gov/products/i ... itcz.shtml

[img]https://i.imgur.com/uWElcXW.jpg[img]

"From June 21-30, the ITF exhibited a large northward advancement in western Africa, and a significant advancement in eastern Africa during the end of June. The mean western (10W-10E) portion of the ITF was approximated at 18.2N, rising well above the climatological normal position by 1.6 degrees. The mean eastern (20E - 35E) portion of the ITF was approximated at 16.6N, very much above the climatological mean position (14.4N) by a remarkable 2.2 degrees. This latest eastern ITF portion anomaly is another significant jump northward from what was already a record postion for mid-June going back to the start of the ITF record in 1989. Figure 1 shows the current position of the ITF relative to the mean climatological (black) position during the 3rd dekad of June and its previous (yellow) position during the 2nd dekad of June. Figures 2 and 3 are time series, illustrating the mean latitudinal values of the western and eastern portion of the ITF, respectively, and their seasonal evolution compared to climatology since April, 2018."

But does it mean stronger waves?

[TheStormExpert]

African waves only seem to be getting stronger, not weaker. In inactive years, is it the opposite? Is there any documented cases of waves being this strong, but the season staying quiet? Just curious.

Likely due to the Kelvin Wave passing by.

[cycloneye]

Interesting thread on Twitter by Eric Webb.

@webberweather
Atlantic MDR may be cold now, but if the EPS monthly verifies w/ a quasi-stationary relaxed trade regime, the Atlantic MDR would warm up a lot going into Aug/Sep, putting some seasonal forecasts in trouble. This also has ENSO implications: a warmer Atlantic resists oncoming Ninos

 https://twitter.com/webberweather/status/1015592309109370882




 https://twitter.com/webberweather/status/1015592511996215297




@webberweather
We're clearly starting to move away from the pattern that made the Atlantic cold in the first place, just goes to show how difficult seasonal forecasting is. Even if the MDR warms a lot it doesn't automatically favor a very active season however given the subtropics are also warm

 https://twitter.com/webberweather/status/1015593879821692928

[Eric Webb]

Interesting thread on Twitter by Eric Webb.

@webberweather
Atlantic MDR may be cold now, but if the EPS monthly verifies w/ a quasi-stationary relaxed trade regime, the Atlantic MDR would warm up a lot going into Aug/Sep, putting some seasonal forecasts in trouble. This also has ENSO implications: a warmer Atlantic resists oncoming Ninos

 https://twitter.com/webberweather/status/1015592309109370882




 https://twitter.com/webberweather/status/1015592511996215297




@webberweather
We're clearly starting to move away from the pattern that made the Atlantic cold in the first place, just goes to show how difficult seasonal forecasting is. Even if the MDR warms a lot it doesn't automatically favor a very active season however given the subtropics are also warm

 https://twitter.com/webberweather/status/1015593879821692928

Now keep in mind this is only showing the Equatorial Atlantic, I'm not entirely sure what the trades look like specifically in the 10-20N belt over the tropical Atlantic but this reduction in trades near the Equator has also coincided w/ the Atlantic warming over the past few weeks or so, it seems like we're going to keep this up going forward. It's a much different pattern than the one that led to the -AMO SST configuration over the Atlantic MDR.